A few days later, more solar eruptions shot out on May 20, slamming Mars with a powerful storm.
In May, the sun unleashed bursts of radiation. When these hit Earth’s magnetic field, they created colorful northern and southern lights. But Earth wasn’t the only target.
From Mars, scientist Shannon Curry reported, “This was the most intense solar event we’ve seen so far.” She leads NASA’s MAVEN mission at the University of Colorado, Boulder.
Solar Storm’s Impact on Mars
When the solar barrage hit, it sparked auroras that wrapped Mars in a shimmering glow stretching from pole to pole. Shannon Curry explained that if astronauts were on Mars, they would have witnessed these auroras firsthand.
Scientists predict these auroras would have appeared jade-green due to the chemistry of Mars’s atmosphere, although surface cameras didn’t capture the colors.
Luckily, no astronauts were present. Mars’s thin atmosphere and lack of a global magnetic shield meant that NASA’s Curiosity rover recorded a radiation exposure akin to 30 chest X-rays—not deadly, but certainly unpleasant for humans.
While the auroras were mesmerizing, they underscored Mars’s perilous, radiation-rich environment. Future astronauts will need to take precautions. “These solar storms are powerful,” Curry warned.
Martian Lava Tubes: Safe Havens from Solar Storms
Lava tubes are long caves formed by volcanic activity on Mars. They could offer robust shelter for Martian explorers during solar storms. However, since harmful solar particles can reach Mars quickly, astronauts need to stay alert.
In simpler terms, as explained by James O’Donoghue, a planetary astronomer at the University of Reading in England, “Martian astronauts must stay updated on space weather forecasts.”
During the mega-eruption on May 20, it became clear how serious the situation was. Mars was hit first by a strong solar flare emitting X-rays and gamma rays.
Quickly following was a powerful coronal mass ejection—a burst of charged particles from the sun. “They seemed really fast to me,” remarked Mathew Owens, a space physicist also at the University of Reading.
Solar Storm Effects on Earth and Mars
When particles from a solar storm hit Earth, they get trapped in our magnetic field and create colorful auroras near the north and south poles. These particles excite gases in the atmosphere, producing vibrant colors that shimmer across the sky.
Unlike Earth, Mars lost its magnetic shield long ago due to its dormant iron core. This means that during May’s solar storm, there was nothing to deflect the incoming particles. “These particles just crash straight into the atmosphere,” explained Nick Schneider, who leads the Imaging Ultraviolet Spectrograph team on NASA’s MAVEN mission at the University of Colorado, Boulder.
As a result, auroras lit up Mars everywhere, captured vividly by the MAVEN orbiter in thunderous ultraviolet glows. On the surface, observers would have seen a light green glow emanating from the excited oxygen atoms in the atmosphere.
